So I finally got around to doing it. I split open my brand new drill, hacked at it's insides, and managed not to destroy it. Just so anyone else who is considering doing this knows, it ain't all peaches...

When you crack open the case, be sure you lift the top half STRAIGHT UP. While it looks like it tucks under the chuck, it does not. Trying to lift up the back (handle side) of the case, then slide it out from under the chuck will cause your gearbox to fall apart. Don't be like me. Lift UP.

Next, the right side of the case is definately the side to take off. It wouldn't work so well the other way around. The battery catch, trigger mechanism, engine and all of the wires are mounted onto the left side of the drill.

Also, make damn sure that you get your gear box back together correctly. Ensure all of the bearings are seated in their little holders, and that the main hammer bearing assembly is not split open. (It splits open EASY if you try to lift and pull back the top half as mentioned above.) This leads to lots of problems, and possible permanant drill damage if you're unlucky. Don't be like me.

12 gauge barrel connectors worked perfectly to splice in the cables. If you do it like I did, and just pigtail them in, you drill will still function with the primary battery pack. If you don't care about that, you could also just cut them, and run direct into them.

I cut the hole in the case with a coping saw. Using a drill, or a pair of cleavers would probabaly work well also.

And finally, the connectors are regular old extention cord ends. Use the female one on the drill so there's never any chance of some yahoo plugging it into 110V AC. Or better yet, use some other kind of connector so no one will ever plug your battery pack into 110V AC to try and charge it. I'll probably change the connectors eventually.

Be sure you wire the two 12v batteries in series (positive to negative), and also be sure you don't get regular starter batteries. Get deep cycle, or in a pinch "Maintenance Free" both of which will vastly outlast the starter batteries when it comes time to discharge and recharge.

Works fine so far. I'll be drilling 3/8 and 1/2 inch holes (probably around a hundred) this weekend. I'll update on how the battery holds up.

Total conversion cost, including a couple of tools, under $100. Oh, and if you haven't bought a wire crimper yet (like you'd use to crimp the wires into the connectors) go ahead and get one. All other tools are poor substitutes, and you don't have much spare wire to work with inside the drill.

I'm very curious to hear how it holds up. How big is that battery pack? It's hard to tell in the pic due to the lack of relativity. Only thing I would do differently would be to use high quality copper barrel connectors, solder it and double heat shrink tube it. If anything ever goes wrong your first thought will turn to those crimps you made on those little yellow splices. A sweet setup would be to have those optima batteries. You could chuck them in a pack and off you go. Electricity is fun to play with. It's always fun to rip apart something expensive and make it your own.

Thank you for sharing your work "foxtrotuniform". This feedback is not intended as a slight or criticism. It's your first try and you were winging it. I hope that others will improve upon your modifications. Enjoy your DIY and building projects. It's so much more rewarding than buying something off the shelf. Look forward to seeing your third generation prototype project.

As someone who has converted a couple dozen Bosch Bulldogs (model #11213 and 11213R) since 1988 to use remote battery packs, and has modified several Bosch Annihilators (#11225vsr and 11225VSRH), I see several improvements to be made.

The best improvement would be to put the motorcycle batteries where they belong (in motorcycles). Having two containers of wet, spillable, sulfuric acid strapped to your body while on approaches or climbing is not a good idea :idea: Forget about "deep cycle" and "maintenance free" batteries.

And "thetroutscout"s idea of Optima batteries is interesting. I love Optima batteries. In fact, I won't use anything else in my Jeeps and 4x4 van. They are sealed, "unspillable" sulfuric acid, and can be run upside down if you wanted to. Yeah, I've winched myself back right-side-up :oops: Unfortunately, each battery weighs 33 to 39 lbs. So two 12volt batteries = 66 to 78 lbs. Perfect for those times when you can drive a pickup truck to the base of the route and belay from the tailgate (like never?).

Do some research on "Sealed Lead Acid" (SLA) batteries, commonly called "gel cells". These are smaller, available in various sizes, and relatively inexpensive at $12 - $25 each. Two powerful 12v batteries in a fanny pack will weigh in at 6 to 12 lbs. Get the type with "Fast-on" (spade) connectors. Usually 3.0Ah (amp-hour) to 7.0Ah in size is right for most climbers. The Annihilator standard battery, Bosch #019 (which may be out of production now) is 1.7Ah @ 24v. Your larger #021 is 3.0Ah @24v. So, two 12v, 3.0Ah SLA's = the power of the large Bosch battery. Two 12v, 6.0Ah SLA's = 2 large Bosch batteries. That's a lot of "firepower".

Since I ditched NiCad batteries 17 years ago, I have not regretted it even once. NiCads have many limitations. The worst is that the expensive factory NiCads go bad after a just a few years. I still use SLA batteries that are 15 years old!

A small SLA battery may be more expensive than a larger size. Look for commonly used sizes (for computer backup power, alarm systems, etc.) as they are more inexpensive.

SLA batteries should be charged slowly, using a 500 to 1000 milliamp (0.5 to 1.0 amp) "smart" automatic-shutoff charger. Gruber makes one for under $20.

Here are a few other tips: There is better electrical cord available. Look at round rubber covered cord. Use a larger size (numerically lower gauge) for less voltage drop, particularly if you will use an extension cord. I have used 50' extension cords for drilling on lead, though 35' is my usual.

The hot male plug from your battery pack is exposed to possible short circuiting. If any metal comes across the male plug, you will be in for fireworks and a nasty meltdown in your pack, car, garage, or home. Better to switch the male plug to the drill and the female plug to the battery pack.

This is aesthetic only, but I cringe when I see the shredded rotohammer housing. Try a coarse round file, or a rotary file, or borrow a body grinder. Please, anything but that saw.

Soldering the connections inside the rotohammer housing would be an improvement over the butt connectors. To prevent the cord from pulling out, there is little room for the easy overhand knot trick inside the housing. Just below your yellow butt connectors, wrap the wires tightly with a few wraps of electrical or duct tape. Pull a bit more cord into the housing, as much as will easily fit. Then wrap with two wire ties ("zip ties"), and cinch tightly. When reassembled, these wire ties will prevent the wires from ripping out. In my case, it's important because the cord extends 5' from the housing to the battery pack (or extension cord), and the cord doubles as a leash in case the rotohammer is dropped. One can add a shock absorbing bungee to this leash.

Hope this helps. Feel free to PM me if you have any specific questions, want links, parts sources, or photos of battery pack modifications.

Thank you for sharing your work "foxtrotuniform". This feedback is not intended as a slight or criticism. It's your first try and you were winging it. I hope that others will improve upon your modifications. Enjoy DIY and building projects. It's so much more rewarding than buying something off the shelf. Look forward to seeing your third generation prototype project.

As someone who has converted a couple dozen Bosch Bulldogs (model #11213 and 11213R) since 1988 to use remote battery packs, and has modified several Bosch Annihilators (#11225VSR and 11225VSRH), I see several improvements to be made.

The best improvement would be to put the motorcycle batteries where they belong (in motorcycles). Having two containers of wet, spillable, sulfuric acid strapped to your body while on approaches or climbing is not a good idea :idea: Forget about "deep cycle" and "maintenance free" batteries.

And "thetroutscout"s idea of Optima batteries is interesting. I love Optima batteries. In fact, I won't use anything else in my Jeeps and 4x4 van. They are sealed, "unspillable" sulfuric acid, and can be run upside down if you wanted to. Yeah, I've winched myself back right-side-up :oops: Unfortunately, each battery weighs 33 to 39 lbs. So two 12volt batteries = 66 to 78 lbs. Perfect for those times when you can drive a pickup truck to the base of the route and belay from the tailgate (like never?).

Do some research on "Sealed Lead Acid" (SLA) batteries, commonly called "gel cells". These are smaller, available in various sizes, and relatively inexpensive at $12 - $25 each. Two powerful 12v batteries in a fanny pack will weigh in at 6 to 12 lbs. Get the type with "Fast-on" (spade) connectors. Usually 3.0Ah (amp-hour) to 7.0Ah in size is right for most climbers. The Annihilator standard battery, Bosch #019 (which may be out of production now) is 1.7Ah @ 24v. Your larger #021 is 3.0Ah @24v. So, two 12v, 3.0Ah SLA's = the power of the large Bosch battery. Two 12v, 6.0Ah SLA's = 2 large Bosch batteries. That's a lot of "firepower".

Since I ditched NiCad batteries 17 years ago, I have not regretted it even once. NiCads have many limitations. The worst is that the expensive factory NiCads go bad after a just a few years. I still use SLA batteries that are 15 years old!

A small SLA battery may be more expensive than a larger size. Look for commonly used sizes (for computer backup power, alarm systems, etc.) as they are more inexpensive.

SLA batteries should be charged slowly, using a 500 to 1000 milliamp (0.5 to 1.0 amp) "smart" automatic-shutoff charger. Gruber makes one for under $20.

Here are a few other tips: There is better electrical cord available. Look for round rubber covered cord, sold by the foot. Get 3 wire (and only use two of the wires). Use a larger size (numerically lower gauge) for less voltage drop, particularly if you will use an extension cord. I have used 50' extension cords for drilling on lead, though 35' is my usual.

The hot male plug from your battery pack is exposed to possible short circuiting. If any metal comes across the male plug, you will be in for fireworks and a nasty meltdown in your pack, car, garage, or home. Better to switch the male plug to the drill and the female plug to the battery pack.

This is aesthetic only, but I cringe when I see the shredded rotohammer housing. Try a coarse round file, or a rotary file, or borrow a body grinder. Please, anything but that saw.

Soldering the connections inside the rotohammer housing would be an improvement over the butt connectors. To prevent the cord from pulling out, there is little room for the easy overhand knot trick inside the housing. Just below your yellow butt connectors, wrap the wires tightly with a few wraps of electrical or duct tape. Pull a bit more cord into the housing, as much as will easily fit. Then wrap with two wire ties, and cinch tightly. When reassembled, these wire ties will prevent the wires from ripping out. In my case, it's important because the cord extends 5' from the housing to the battery pack (or extension cord), and the cord doubles as a leash in case the rotohammer is dropped. One can add a shock absorbing bungee to this leash.

Hope this helps. Feel free to PM me if you have any specific questions, want links, parts sources, or photos of battery pack modifications.

I'll be curious to see what kind of run-time you end up getting out of those mods. Thanks for the pictures.

John:

In response to the male end of the plug-in coming off of the battery and female end coming off the drill, I did the same thing on mine with the thought that I never wanted someone to accidentally plug it into 110v and fry everything. I know what you're thinking, but you just never know who might be around your drill sometime in the future. The hot plug-end on the battery can be easily shielded by getting an old discarded female plug-end with the wiring cut off tight and plugging the battery plug into it. Then you simply remove it and plug into the drill when it's time to rock and roll.

You can also try taking the old battery, remove the guts of the pack and wire it the terminals inside the pack, seal it up and then you do not have to cut into the case, no worries about people plugging it in, ( as it is the battery itself), no worries about opening up the drill, no added weight since the old battery case is now empty, no need for pigtails, etc. Essentially, remove the guts and use new guts with an extended lead in. I found an old battery at batteries plus and they gave it to me for free.

You can also try taking the old battery, remove the guts of the pack and wire it the terminals inside the pack, seal it up and then you do not have to cut into the case, no worries about people plugging it in, ( as it is the battery itself), no worries about opening up the drill, no added weight since the old battery case is now empty, no need for pigtails, etc. Essentially, remove the guts and use new guts with an extended lead in. I found an old battery at batteries plus and they gave it to me for free.

You can also try taking the old battery, remove the guts of the pack and wire it the terminals inside the pack, seal it up and then you do not have to cut into the case, no worries about people plugging it in, ( as it is the battery itself), no worries about opening up the drill, no added weight since the old battery case is now empty, no need for pigtails, etc. Essentially, remove the guts and use new guts with an extended lead in. I found an old battery at batteries plus and they gave it to me for free.

I agree with you, but I only have a brand new battery, and I didn't want to sacrifice the capability to use it. I won't ALWAYS need to drill tons of holes. The stock pack is enough for a single route, so the aftermarket one will stay home most of the time.

I see what you're saying though, and had I had a battery case, I probably would have gone that route. Eliminates the need to take apart the drill and risk destroying it.

Thank you for sharing your work "foxtrotuniform". This feedback is not intended as a slight or criticism. It's your first try and you were winging it. I hope that others will improve upon your modifications. Enjoy DIY and building projects. It's so much more rewarding than buying something off the shelf. Look forward to seeing your third generation prototype project.

As someone who has converted a couple dozen Bosch Bulldogs (model #11213 and 11213R) since 1988 to use remote battery packs, and has modified several Bosch Annihilators (#11225VSR and 11225VSRH), I see several improvements to be made.

The best improvement would be to put the motorcycle batteries where they belong (in motorcycles). Having two containers of wet, spillable, sulfuric acid strapped to your body while on approaches or climbing is not a good idea :idea: Forget about "deep cycle" and "maintenance free" batteries.

And "thetroutscout"s idea of Optima batteries is interesting. I love Optima batteries. In fact, I won't use anything else in my Jeeps and 4x4 van. They are sealed, "unspillable" sulfuric acid, and can be run upside down if you wanted to. Yeah, I've winched myself back right-side-up :oops: Unfortunately, each battery weighs 33 to 39 lbs. So two 12volt batteries = 66 to 78 lbs. Perfect for those times when you can drive a pickup truck to the base of the route and belay from the tailgate (like never?).

Do some research on "Sealed Lead Acid" (SLA) batteries, commonly called "gel cells". These are smaller, available in various sizes, and relatively inexpensive at $12 - $25 each. Two powerful 12v batteries in a fanny pack will weigh in at 6 to 12 lbs. Get the type with "Fast-on" (spade) connectors. Usually 3.0Ah (amp-hour) to 7.0Ah in size is right for most climbers. The Annihilator standard battery, Bosch #019 (which may be out of production now) is 1.7Ah @ 24v. Your larger #021 is 3.0Ah @24v. So, two 12v, 3.0Ah SLA's = the power of the large Bosch battery. Two 12v, 6.0Ah SLA's = 2 large Bosch batteries. That's a lot of "firepower".

Since I ditched NiCad batteries 17 years ago, I have not regretted it even once. NiCads have many limitations. The worst is that the expensive factory NiCads go bad after a just a few years. I still use SLA batteries that are 15 years old!

A small SLA battery may be more expensive than a larger size. Look for commonly used sizes (for computer backup power, alarm systems, etc.) as they are more inexpensive.

SLA batteries should be charged slowly, using a 500 to 1000 milliamp (0.5 to 1.0 amp) "smart" automatic-shutoff charger. Gruber makes one for under $20.

Here are a few other tips: There is better electrical cord available. Look for round rubber covered cord, sold by the foot. Get 3 wire (and only use two of the wires). Use a larger size (numerically lower gauge) for less voltage drop, particularly if you will use an extension cord. I have used 50' extension cords for drilling on lead, though 35' is my usual.

The hot male plug from your battery pack is exposed to possible short circuiting. If any metal comes across the male plug, you will be in for fireworks and a nasty meltdown in your pack, car, garage, or home. Better to switch the male plug to the drill and the female plug to the battery pack.

This is aesthetic only, but I cringe when I see the shredded rotohammer housing. Try a coarse round file, or a rotary file, or borrow a body grinder. Please, anything but that saw.

Soldering the connections inside the rotohammer housing would be an improvement over the butt connectors. To prevent the cord from pulling out, there is little room for the easy overhand knot trick inside the housing. Just below your yellow butt connectors, wrap the wires tightly with a few wraps of electrical or duct tape. Pull a bit more cord into the housing, as much as will easily fit. Then wrap with two wire ties, and cinch tightly. When reassembled, these wire ties will prevent the wires from ripping out. In my case, it's important because the cord extends 5' from the housing to the battery pack (or extension cord), and the cord doubles as a leash in case the rotohammer is dropped. One can add a shock absorbing bungee to this leash.

Hope this helps. Feel free to PM me if you have any specific questions, want links, parts sources, or photos of battery pack modifications.

I agree with everything. I chose these batteries because they were avaliable in the local area, and have a high capacity for the money.

I agree on better electrical cord, and the connectors. I hadn't thought about the hot lead on the battery end. I'll transport my batteries with the series wire disconnected on one end. That should safen things up a bit.

And I LOVE the saw! I treat my tools wether they be my truck or my drill like tools! Function over form any day of the week. You should see the paint on my 4runner. The other day one of my friends said, "Oh my god it's so scratched up! That's so sad!"

Thanks for the advice! Much good info in there. Hopefully the next person modding a drill will read your post and take it to heart!

foxtrot, congrats on the DIY. It's a great feeling to take something that you have and modify it to your needs. And if there are improvements to be made all the better; move fun to be had and more things to learn!

some one mentioned about the cord getting pulled out of the drill, here's a little tip (back from my days of being an electrician....take a zip-strap (cable tie) and put it around the cord on the INSIDE side of the cord, this way if its pulled on, its not pulling on the butt-connectors, it'll pull on the zap-strap which will act as a stopper when it hits the body of the drill...hope that makes sense

cool...i'm just getting into hand drilling myself, course, if i ever need a hammer drill, i can just borrow my dads hilti

I have just done the same thing with my drill, just on a smaller scale: 1) started with a Chicago Electric 18v rotary hammer drill (came with 2 1.7Ah battery packs, which just weren't cutting it in hard rock) 2) drilled a hole straight up through the handle, from the bottom to the trigger 3) cut 1' off the male end of a 5-6' computer power extension cord 4) soldered the cable onto the incoming power contacts on the trigger, being sure to knot the cable inside the housing: 5) connected 3 6v 4.2Ah gel-cells (sealed lead acid) in series, and attached the rest of the cable onto those 6) closed drill housing, taped batteries together, attached the 2: TADA! Seems to work alright.

That is pretty sweet, and I considered doing something similar by disassembling one of the old battery packs. I really like the coiled cord idea too. There would be 2 problems with this though: 1) neither the OP or myself have a Hilti :roll: 2) I cant find a price anywhere, but chances are it is going to cost quite a bit more than the *free* computer cable and 1/2hr. of my time that I spent.

The saga continues..... 7) I created a wooden box with a hinged lid out of 3/4" plywood. The batteries fit very tightly within the box, and the power cable extends out one side through a hole (wrapped and tied off tightly with wire on the inside, to keep it from getting pulled out). Final weight=3.5kg: http://www.rockclimbing.com/...p.cgi?Detailed=67447http://www.rockclimbing.com/...p.cgi?Detailed=67448Have tested the pack once. I was able to drill twice as many holes at full power, but even after the power dropped some, I was able to keep drilling further. The biggest benefit seems to be that the gel-cells do not heat up like the original battery packs did.

Apologies if this is an overly obvious question, but... Are you trying to put in the proper sds bit? I ask in the event that you are not aware that there are two types (plus and max) which are not interchangeable. A standard bit will not work either, but you probably know that.

So this is embarrassing...I bought an Annihilator used online with no battery. Had someone modify it with a new hand made battery/fanny pack combo and it's good to go.

I go to put a bit into it....annnnd can't figure that part out. It seems like there are no teeth inside the chuck. What am I missing?

The Annihilator should use a standard sds bit, just put the bit in the chuck and push on it while turning the bit. Once the groves line up with the right part the bit will slide all the way in until it clicks into place.

To remove the bit, grab the chuck and pull it back towards the drill while simultaneously pulling the bit out.

Just grabbed an SDS plus bit and it works no problem. Thanks! The other bit I had (no packaging, was told it was the correct type) doesn't have the same notches as the Plus so clearly it wasn't the right kind,